A need has been found for walkers and runners in an environment where a faster moving person or a person on a vehicle, such as a bicycle, may approach a walker/runner from behind on a walking/running path, bicycle path, road or similar area where walkers, runners and bicycles (or other vehicles) are used, particularly when a walker or runner is using earphones and listening to music or something transmitted into the earphones or earbuds. A Bluetooth-enabled device can be worn on the backside of an individual (belt, collar, waistband, shoe, hat or similarly attached to communicate rearwardly) that detects movement approaching the wearer from the rear and interrupts or otherwise alerts the person to the oncoming danger, be it accidental danger, intentional danger (in the case of a mugger), or as an added measure of self-awareness, such as a construction worker having a person or persons located in the same area or working in the same area behind the worker. Upon detection of movement, the device can vibrate, emit a sound or transmit another signal to the wearer's cell phone App which then can be transmitted to the user's earphones, headphones, earbuds, and/or can emit a signal directly from the cellphone or other device. The technology described can also be built into and integrated directly within a cell phone, if so desired, potentially using the processor, sensor or battery already present within the cell phone.
Depending on settings and preferences, the App can cause the cell phone or wearable device to vibrate, emit a custom alarm or send a tone to earphones, headphones or earbuds to notify wearer of a person (or person on a bicycle, etc.) approaching from the rear. The wearer can set the App for various possible scenarios, with potential different resulting alarms or tones.